Compression ignition engine power plant



Jan. 6, 1953 J. A. BENNETT-POWELL 2,624,849

COMFRESSION IGNITION ENGINE POWER PLANT 2 SHEETS-SHEET 2 Filed July 25, 1949 Patented Jan. 6, 1953 CMPRESSTGN IGNITION ENGINE POWER PLANT .lohn Ambrose Bennett-Powell, Tendring, England, assigner to Fell Developments Limited, London, England, a British company Application July 25, 1949, Serial No. 106,670 In Great Britain August 17, 1948 5 Claims. l

rThis invention relates to compression ignition engine plants, and particularly but not exclusively to multiple engine power plants such as are described in the specincation of application No. 6%,613 iiled August 29, 1946, or of application No. '793583 iiled December 26, 1947, both by L. n. neil.

ln operating such power plants to give high torrides at low speed, cooling of the main engines presents certain problems. The heat to -be dissipated from a diesel engine is approximately directly proportional to the power output, except that at low speeds under load, such as are encountered in starting a vehicle when the power plant is used for traction purposes, the quantity of heat to be dissipated is somewhat greater than that indicated by this relationship. Direct mechanical drive of cooling means, such as fans or water pumps, from the main engine or engines will not be suitable since cooling will either be inadequate at low speeds or excessive at high speeds or both. saine objection applies to direct drive from the auxiliary engine or engines described in the spccications referred to above, since the speed of such engine or engines also increases with increased main engine speed.

The object of the present invention is to provide, in power plants as indicated above, a drive for the cooling means which will enable their cooling capacity to be substantially commensurate with the heat dissipation requirements of the power plant under running conditions.

A compression ignition power plant arranged to give torque at low speed is provided, according to the present invention, with cooling means operated electrically at a speed which gives a rate of heat dissipation substantially equivalent to the rate of heat generation in the main engine. Thus `for substantially constant power output trom the power plant, substantially constant- .speed operation of the cooling means is required, while for a power plant giving higher power output at lower than at higher speeds it will be necessary to operate the cooling means at high speed 'when the power plant is at low speed and vice versa.

More specincally stated, a compression ignition power plant arranged to give substantially constant power output over its running speed range is provided, according to the present invention, with cooling means operated by a direct current motor or motors supplied from a direct current generator fitted with an automatic voltage regulator to ensure :substantially constant output voltage.

The constant voltage direct current generator is preferably driven from an auxiliary engine such as the engine which drives the blower descrised in the specifications referred to above, in order to leave the output of the main engine or engines unimpaired.

it is generally preferable to neglect the supernorznal heat dissipation requirements at low speeds under load, since the period of slow running is short and generally occurs when the coolant and the engines are relatively cool, so that the heat not dissipated by the cooling means gives more rapid increase of engine temperature to operating temperature, which is generally advantageous.

in a tour-engine power plant such as that described in the specification of application No. 793,903, above referred to a constant voltage direct current generator may be associated with and driven by each of the two auxiliary engines and the cooling means and other auxiliary apparatus, arranged to provide substantially equal loads for each generator. In such an arrangement, the use of electrical drive for the cooling means and other auxiliary apparatus has the advantage that it is easy to transfer the drive for any given unit of the cooling means or auxiliary apparatus from one auxiliary engine to the other by switching it from one generator to the other.

By arranging for the direct current generator to start the main engines as well as driving the cooling means and other auxiliaries, large starter batteries for the main engines are eliminated.

The invention further consists in the new or improved features, arrangements and combinations oi parts embodied in the preferred form of the invention which it is now proposed to describe in some detail with reference to the accompanying drawings in which:

Figure l shows a side elevation of a locomotive embodying the present invention with the major portion of the external Cowling removed to show the principal components of the locomotive.

Figure 2 shows a plan view of the locomotive shown in Figure l (all cowling having been removed and omitting electrical wiring as shown in Figure 1).

Figure 3 shows a wiring diagram of the electrical system of the present invention which is embodied in the locomotive of Figures 1 and 2.

Figure 4 shows a modiiication of Figure 3.

Referring now to Figures l and 2, the locomotive shown is provided with a power plant comprising four compression ignition engines A, B, C, D situated in pairs A, B and C, D near the ends of the locomotive chassis. The output from each of these engines is taken by suitable transmission means which form no part of the present invention, to a gear box I arranged substantially centrally in the locomotive chassis and thence to the driving wheels of the locomotive. Auxiliary internal combustion engines E and F drive blowers G and H by means of chain drives 81 and 88 respectively, these blowers G and H supply air through pipes K and L to supercharge the engines A, B, C and D. By means of this supercharging and also by means of control means indicated generally by 5S, 5I, 52 and 53 for fuel injection pumps 54, 55, 56 and 51 of engines A, B, C and D respectively, the engines A, B, C and D may be made to give substantially constant power output over their running speed range as explained in more detail in the specification of copending application No. 109,635 dated August 11, 1948, by L. F. R. Fell and R. J. W. Cousins; control of the auxiliary engines in response to supercharge pressure as referred to in this copending application is provided by pressure sensitive devices 58, 59 for engines E and F respectively. Pipes EB and GI connect devices 58 and 59 respectively to pipes K and L. Starter motors 'VI and 'I8 are provided for auxiliary engines E and F respectively.

Cooling means for the locomotive power plant comprise radiators 62 and 63 for pairs of engines A, B and C, D respectively, fans 64 and 65 associated with radiators 62 and 63 respectively to ensure relative motion of air over the radiators to cool them, and water circulating pumps 6E, 6l, @il and S9 for engines A, B, C and D respectively. Fans 54 and 55 are driven by motors M'I and M5 respectively. Pumps 66 and 6l are driven by motor Mt and pumps 68 and 69 are driven by motor M6. Radiators 62 and 63 are principally employed for cooling the water which circulates through the cylinder jackets of the main engines but may have certain of their cooling elements arranged to cool oil from the main engine oil circulating systems as is well known in large engine installations.

The locomotive is also provided with a boiler d l for train heating purposes and motors MI I and M I2 are provided for the feed pump and blower respectively of this boiler.

Exhauster pumps 'I3 and 'M are provided for supplying the vacuum system of the locomotive, and are driven by motors M9 and MID respectively.

The electrical power for the locomotive is provided by generators GI and AGI driven by auxiliary engine E and generators G2 and AG2 driven by auxiliary engine F. The associated generators in each pair are conveniently arranged on common shafts l5 and 'I6 respectively as shown.v

Generators GI and G2 are 24 volt direct current generators and generators AGI and AG2 are 90 volt direct current generators. Generators AGI and AG2 are provided with voltage regulators VRI and VR2 respectively. Storage batteries BI and B2 are charged by generators Gl and G2 respectively.

Control panels 89 and 9B are provided one in each driving cab of the locomotive and accommodate various components such as switches and indicating lights as is clear from Figure 3 which indicates panel 99 in chain line. Motors PPI, FP2, PPS and PF4 drive oil pumps 79, 8|, 3 and 35 associated with engines C, D, A and B respectively for a purpose explained in more detail below.

Elements Sil, 82, 85 and 86 associated respectively with engines C, D, A and B. @110171011 t0. in#

' nuence the electrical system shown in Figure 3 in accordance with the oil pressure in the various engines as will be described in more detail below.

rTurning now to Figure 3, this shows a wiring diagram or" the connections between the generators Gl and AGI and the auxiliaries associated with engines C and D, as well as the connections which are relevant to motors M9, Mill, Ml I and MI2 shown on the side of the change-over links 23 and 24 which is removed from generators GI and AGI. The circuit arrangements for generators G2 and AG2 and the auxiliaries associated with engines A and B are identical with those provided for generators GI and AGI and the auxiliaries associated with engines C and D and have been omitted for the sake of clarity. In other words the complete circuit diagram for the electrical system of the locomotive involves, in addition to what is shown in Figure 3, a duplication of the circuits shown above the change-over links 2-3 and 24.

The circuit comprising the generator GI and shown to the left of this generator, includes the 24 volt battery BI and certain starting arrangements. The battery Bi is part of the general electrical system of the power plant and supplies current for purposes such as lighting and starting the auxiliary engine and, in some cases, for relays used in the general control system of the power plant.

The circuit comprising the generator AGI, includes motors MI and M2 for starting the main engines C and D and motors M5 and M6 for driving the radiator cooling fan and the water pumps 88 and 69.

The circuit shown below change-over links 23 and 2d comprises motors M9, MIEI, MII and MI2. A switch S2 permits the motors MII and MI2 to be disconnected while motors M9 and MIG remain in circuit, since the train-heating boiler it will not always be used.

r1`he exhauster motor M9 drives the booster exhauster i3 which is normally only required to function during and after the operation of the brakes. It thus works intermittently, and is generally required to start under a heavy load and is accordingly provided with an independent switch EX! operated by a coil EXI which is energised -by a switch Cab A or Cab B mounted on the drivers brake levers IBI and |053 respectively, according to which cab of a two-cab locomotive the driver is occupying. A field resistance and associated snorting-out switch EX2 controlled by a coil EXZ automatically provide for two-speed operation of the motor M in a known manner.

The generator GI supplies current to the eld coil FCi of the generator AGI; this field coil is associated with the carbon pile voltage regulator VRI and a dropping resistance AFI which is provided with a shorting switch AG.

Battery cut-oir switches BCOI and BCO2 are provided to break the connection with the battery Bl when the voltage supplied by the generator Gl falls below the battery voltage; these switches are operated by coils BCCI and BCC2 respectively.

The procedure on starting is as followsrhe auxiliary engine E is first started in the usual manner by means of the starter motor TI, which is energised from the battery BI. The auxiliary engine E attains a speed set by its governor and drives the generator GI and the generator AGI, the former supplying field current to the latter.

To start the main engines C and D, the switch SI is set to the Start position shown, thereby lighting the Start indicating light LI. To start the first main engine, the starting button SBI is pressed thus energising the coil OPI. The coil OPI closes a switch OPI thus supplying current from the battery BI to the motor PPI whi-ch drives the pump 'I9 (Figures l and 2) arranged to draw oil from the engine sump and to deliver it via a non-return valve into the pressure feed oil circuit. When a sufficient oil pressure has been built up to flood the crankshaft bearings and other localities, a switch PSI is closed by the action of an element 80 sensitive to oil pressure. The closing of the switch PSI energises the coil SMI and the governor solenoid GSI which is part of control means 52 and arranged to actuate the engine fuel pump to give full fuel injection on starting and thus functions in the same way as solenoid 26 in Figure l of the drawings acf companying application No. 109,635 filed August ll, 1948, by L. F. R. Fell and R.. J. W. Cousins. The coil SMI closes the switch SMI, opens the switch SMI and thus connects the starter motor MI across the generator AGI which is giving approximately 24 volts output by reason of the resistance AFI in its field circuit. As soon as the first main engine is running, the second main engine is started in the same way, involving pressing starting button SBZ, opening of switch SM2' and the closing of switch SM2, and the switch SI is then put to Runf The result of this is to light the Run indicating lamp L2 and energise the coils AF and A, thus closing the shorting switch AF of the resistance AFI opening the switch AI and closing the switch A2, which connects the generator AGI, now giving 90 volts output, with the motors M5, M6, MII), and provided that the switches EXI and S2 are closed, with motors M9,MII andMI2.

Mechanical interconnections shown in broken lines may also be provided between the moving elements of the following pairs of switches SMI and SMI', AI and A2, SM2 and SM2', which ensure that their action is as described above, and that the generator, when giving 24 volts output is only loaded with motors M I and M2, and that these motors cannot receive the 90 volts output of the generator AGI.

Fuses are provided as shown for each motor and do not require any description as they are of known type.

Thev use of a 90 volt supply for the motors M5, M6, M9, MII), MII and MIE as described above represents a compromise between the weight of these motors (which must not be too large) on the one hand and insulation requirements and fire risks on the other hand, which is convenient for a general purpose railway locomotive.

In the case of a power plant with four main and two auxiliary engines as illustrated in Figures l and 2 it is generally preferred that each auxiliary engine should provide the drive for the cooling means of the associated pair of main engines whereas the change-over links 23 and 24 allow motors M9, MII), MII and MIZ to be driven by the generator associated with either auxiliary engme.

In the case of a four engine power plant referred to above, the output of each of the 90 volt generators may be such that either of them could drive all the required motors alone; such an arrangement would prevent the failure of current provided by one auxiliary engine from interfering with the operation` of the locomotive. However, since failure of an auxiliary engine, and the resulting stoppage of the two associated main engines, is more likely than current failure, it is generally satisfactory to provide the generators of sufficient power to supply motors as shown on the drawing.

The electrical system described above is based on the assumption that the power plant will give substantially constant power output and hence require substantially -constant-speed drive for the cooling means. It will be appreciated, however, that it is easy to modify the system described to provide any desired relationship between the speed at which the cooling means are operated and the operating condition of the power plant, for example, the cooling means may be controlled according to the temperature of the cooling system of the power plant, by means of one or more temperature sensitive elements, acting through suitable relays if necessary to vary the supply of current to, and hence the speed of, the electrical motors driving the -cooling means. In this way, substantially thermostatic control of the cooling system may be obtained.

One way of providing such thermostatic control is shown diagrammatically in Figure 4, where the circuit of the motor M5, which drives cooling fan 65, is shown with the necessary modifications. In this drawing the motor M5 is a shuntwound motor and the current in its field coil is varied 'by the variable resistance comprising resistor 91, and arcuate strip 9| both contacted by movable pivoted arm 82. The arm 92 is connected by link 93 to a bellows 94 to which is connected a pipe having its closed end 96 located within the radiator 63. The pipe S5 and bellows 94 are filled with some suitable fluid, for example a volatile organic liquid which will exert a pressure within the bellows 94 corresponding to the temperature of the radiator water or vapour surrounding the pipe end 95.

As shown, the pivoted arm 92, link 93 and bellows 94 are in the position corresponding to low temperature within the radiator 63, where current to the field coil of motor M5 has to pass through the maior portion of the resistor 91 thus causing motor M5 to run at low speed. As the temperature in radiator 63 increases, the pressure generated within bellows 94 causes the pivoted arm 92 to swing in a clockwise direction thus reducing the portion of the resistor 91 in series with the field coil of motor M5 and hence increasing the speed of the motor M5. It will be appreciated that identical arrangements may be made in respect of motors M6, M'I and M8 and that, if required, known relays may be used to augment the power exerted by the bellows 94.

I claim:

l. A compression ignition power plant comprising a main compression ignition engine, a blower for said main engine, an independent auxiliary engine to drive said blower, means for controlling said main engine and said auxiliary engine to cause said main engine to give substantially constant power output over its running speed range, cooling means for said main engine, means for producing motion of cooling fluid in relation to said cooling means, a rst generator driven by said auxiliary engine, a second generator driven by said auxiliary engine and arranged to give a higher output voltage than said first generator, an automatic voltage regulator to maintain substantially constant the output voltage of said second generator, connecting means whereby said rstgenerator supplies a battery oi the general electrical system of the power plant and energises the neld of said second generator, a direct current motor supplied by said second generator and means for causing said motor to drive said means for producing motion of cooling fluid.

2. A compression ignition power plant comprising a main compression ignition engine, a blower for said main engine, an independent auxiliary engine to drive said blower, a means for controlling said main engine and said auxiliary engine to cause said main engine to give substantially constant power output over its running speed range, cooling means for said main engine, means `for producing motion of cooling fluid in relation to said cooling means, a first generator driven by said auxiliary engine, a second generator driven by said auxiliary engine, an automatic voltage regulator to maintain substantially constant the output voltage of said second generator, control means to cause said second generator. to give a lower output voltage substantially equal to the output voltage of said rst generator and a higher voltage output higher than that of said rst generator, connecting means whereby said rst generator supplies a battery of the general electrical system of the power plant and energises the iield of said second generator, a starter motor for said main engine, means for supplying said starter motor with the lower output voltage from saidsecond generator, a direct current motor, means for supplying said direct current motor with the higher voltage output from said second generator and means for causing said direct current motor to drive said means for producing motion of cooling iiuid.

3. A compression ignition power plant comprising a main compression ignition engine, a blower forv said main engine, an independent auxiliary engine to drive said blower, means for controlling said main engine and said auxiliary engine to cause said main engine to give ,substantially constant power output over its running speed range, cooling means for said main engine, means for producing motion of cooling fluid in relation to said cooling means, a iirst generator driven by said auxiliary engine, a second generator driven by said auxiliary engine, an automatic voltage regulator to maintain substantially constant the output voltage of said second generator, control means to cause said second generator to give a lower output voltage substantially equal to the output voltage of said rst generator and a higher voltage output higher than that of said first generator, connecting means whereby said rst generator supplies a battery of the general electrical system of the power plant and energises the eld of said second generator, a starter motor for said main engine, means for supplying said starter motor with the lower output voltage from said second generator, a direct current motor, means for supplying said direct current motor with the higher voltage output from said second generator, means for causing said direct current motor to drive said means for producing motion of cooling iiuid and means to prevent the higher voltage output of said second generator from being applied to said starter motor and to prevent said second generator from being loaded with said direct current motor when giving its lower voltage output.

A compressionignition power plant comprising a main compression ignition engine, a blower for said main engine, an independent auxiliary engine to drive said blower, means for controlling said main engine and said auxiliary engine to cause said main engine to give substantially constant power output over its running speed range, cooling means for said main engine, means forprodu-cing motion of cooling uid in relation to said cooling means, a first generator driven by said auxiliary engine, a second generator driven by said auxiliary engine and arranged to give a higher output Voltage than said rst generator, an automatic voltage regulator to maintain substantially constant the output of said second generator, connecting means whereby said first generator supplies a battery of the general electrical system of the power plant and energises the iield of said second generator, a. first direct current motor supplied by said second generator, means for causing said motor to drive said means for producing motion of cooling fluid, a second direct current motor for driving auxiliary apparatus not associated with said cooling means and means for supplying said second motor with the voltage output from said second generator.

5. A compression ignition power plant as claimed in claim 4 in which alll elements, with the exception of said second direct current motor are duplicated and means are provided to connect said second direct -current motor with either of the two second generators.

J O-HN AMBROSE BENNETT-POWELL.

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